Low-loss high-repetition-rate pulsed laser modulator

Abstract

The present invention provides a low-loss high-repetition-rate pulsed laser modulator comprising: a 2*2, 1:1 coupler; a light delay module; a 1*2, 1:1 coupler. The present invention can modulate a low-repetition-rate pulsed laser to be a high-repetition-rate pulsed laser. The basic principle is: one beam of low-repetition-rate pulsed laser can be divided into two beams with the same light intensity by a 1*2, 1:1 coupler; control the two beams of light to have an optical path difference so that when they are coupled into a 2*2, 1:1 coupler, a double pulse repetition rate can be obtained; In the same way, when the two beams of light from former 2*2, 1:1 coupler, with another different optical path difference are coupled into the next 2*2, 1:1 coupler, a double pulse repetition rate can be obtained again; when we obtain the repetition rate we need, a 1*2, 1:1 coupler instead is connected to couple the two beams of light into one beam with a double repetition rate.

We claim: 
     
       1. A low-loss high-repetition-rate pulsed laser modulator comprising:
 two 1*2, 1:1 couplers configured as an input end and an output end of the modulator respectively; 
 at least two light delay modules arranged on a same light path between the two 1*2, 1:1 couplers; and 
 at least one 2*2, 1:1 coupler with each arranged between two adjacent light delay modules; 
 wherein the light delay modules are configured to control path-length difference Δl according to the following formula: 
 
       
         
           
             
               
                 
                   Δ 
                   ⁢ 
                   
                       
                   
                   ⁢ 
                   l 
                 
                 = 
                 
                   
                     ( 
                     
                       kt 
                       + 
                       
                         t 
                         2 
                       
                     
                     ) 
                   
                   · 
                   
                     c 
                     n 
                   
                 
               
               ; 
             
           
         
         where, c is a velocity of light in vacuum, n is a refractive index of fibers, k is a natural number, and t is time difference between two neighboring pulses respectively transmitted in two light paths.